硅橡膠是指主鏈由硅(gui)和氧原子(zi)交替構成(cheng),硅(gui)原子(zi)上通常連有兩個有機基團的(de)(de)橡(xiang)(xiang)膠。普(pu)通的(de)(de)硅(gui)橡(xiang)(xiang)膠主要由含甲(jia)基和少量乙烯(xi)基的(de)(de)硅(gui)氧鏈節組成(cheng)。苯(ben)基的(de)(de)引入可提(ti)高硅(gui)橡(xiang)(xiang)膠的(de)(de)耐(nai)(nai)高、低溫性(xing)(xing)(xing)(xing)能,三(san)氟丙基及氰基的(de)(de)引入則(ze)可提(ti)高硅(gui)橡(xiang)(xiang)膠的(de)(de)耐(nai)(nai)溫及耐(nai)(nai)油(you)性(xing)(xing)(xing)(xing)能。硅(gui)橡(xiang)(xiang)膠耐(nai)(nai)低溫性(xing)(xing)(xing)(xing)能良(liang)好,一般(ban)在-55℃下仍能工作(zuo)。引入苯(ben)基后,可達-73℃。硅(gui)橡(xiang)(xiang)膠的(de)(de)耐(nai)(nai)熱性(xing)(xing)(xing)(xing)能也很突(tu)出(chu),在180℃下可長期工作(zuo),稍高于200℃也能承受數(shu)周或(huo)更長時(shi)間仍有彈性(xing)(xing)(xing)(xing),瞬時(shi)可耐(nai)(nai)300℃以上的(de)(de)高溫。硅(gui)橡(xiang)(xiang)膠的(de)(de)透氣(qi)性(xing)(xing)(xing)(xing)好,氧氣(qi)透過率在合成(cheng)聚合物(wu)中(zhong)是較(jiao)高的(de)(de)。此外,硅(gui)橡(xiang)(xiang)膠還具有生(sheng)理惰(duo)性(xing)(xing)(xing)(xing)、不會導致凝血(xue)的(de)(de)突(tu)出(chu)特性(xing)(xing)(xing)(xing),因此在醫(yi)用(yong)(yong)領域應用(yong)(yong)廣泛。
主要品種
硅(gui)(gui)(gui)橡(xiang)膠分(fen)類的方法很多(duo),通常按固化前的形態(tai)分(fen)為(wei)固體硅(gui)(gui)(gui)橡(xiang)膠和液(ye)體硅(gui)(gui)(gui)橡(xiang)膠;按硫化溫(wen)(wen)度分(fen)為(wei)室溫(wen)(wen)硫化硅(gui)(gui)(gui)橡(xiang)膠,高溫(wen)(wen)硫化硅(gui)(gui)(gui)橡(xiang)膠;按所(suo)用(yong)(yong)單體的不(bu)同(tong),可分(fen)為(wei)甲基(ji)(ji)乙烯基(ji)(ji)硅(gui)(gui)(gui)橡(xiang)膠,甲基(ji)(ji)苯基(ji)(ji)乙烯基(ji)(ji)硅(gui)(gui)(gui)橡(xiang)膠、氟(fu)硅(gui)(gui)(gui),腈硅(gui)(gui)(gui)橡(xiang)膠等(deng);按性能和用(yong)(yong)途(tu)的不(bu)同(tong)又可分(fen)為(wei)通用(yong)(yong)型、超耐低(di)溫(wen)(wen)型、超耐高溫(wen)(wen)型、高強力(li)型、耐油(you)型、醫用(yong)(yong)型等(deng)等(deng)。
發展史
硅(gui)(gui)橡(xiang)膠(jiao)(jiao)早期是由美國以(yi)三氯(lv)化鐵為催化劑合(he)成的(de)。1945年(nian),硅(gui)(gui)橡(xiang)膠(jiao)(jiao)產品問世。1948年(nian),采用高(gao)比表面積的(de)氣相法白(bai)炭黑(hei)補強的(de)硅(gui)(gui)橡(xiang)膠(jiao)(jiao)研制(zhi)成功,使(shi)硅(gui)(gui)橡(xiang)膠(jiao)(jiao)的(de)性能躍(yue)升到實(shi)用階段,奠(dian)定了現代硅(gui)(gui)橡(xiang)膠(jiao)(jiao)生(sheng)(sheng)產技(ji)術的(de)基礎。從二甲基二氯(lv)硅(gui)(gui)烷合(he)成開始生(sheng)(sheng)產硅(gui)(gui)橡(xiang)膠(jiao)(jiao)的(de)國家有美國。俄羅(luo)斯、德國、日本、韓國和(he)中(zhong)(zhong)國等(deng)。中(zhong)(zhong)國硅(gui)(gui)橡(xiang)膠(jiao)(jiao)的(de)工業(ye)化研究始于1957年(nian),多家研究所(suo)和(he)企業(ye)陸續開發出各種硅(gui)(gui)橡(xiang)膠(jiao)(jiao)。到2003年(nian)底,中(zhong)(zhong)國硅(gui)(gui)橡(xiang)膠(jiao)(jiao)生(sheng)(sheng)產能力(li)為135千噸(dun),其中(zhong)(zhong)高(gao)溫膠(jiao)(jiao)100千噸(dun)。
高溫硫化硅橡膠
高(gao)(gao)(gao)溫硫化(hua)(hua)(hua)硅(gui)橡膠(jiao)是(shi)(shi)指聚(ju)硅(gui)氧(yang)烷變成(cheng)彈性(xing)體的過(guo)程是(shi)(shi)經過(guo)高(gao)(gao)(gao)溫(110-170℃)硫化(hua)(hua)(hua)成(cheng)型的。它(ta)主要(yao)以高(gao)(gao)(gao)分子量(liang)的聚(ju)甲基乙烯基硅(gui)氧(yang)烷為生膠(jiao),混入補強填料(liao)、硫化(hua)(hua)(hua)劑等,在加(jia)(jia)熱加(jia)(jia)壓(ya)下(xia)硫化(hua)(hua)(hua)成(cheng)彈性(xing)體。硅(gui)橡膠(jiao)的補強主要(yao)是(shi)(shi)各(ge)種(zhong)類型的白炭黑,可使(shi)硫化(hua)(hua)(hua)膠(jiao)的強度(du)增加(jia)(jia)數十(shi)倍(bei)。有(you)時為了降(jiang)低成(cheng)本或改善膠(jiao)料(liao)性(xing)能及(ji)賦(fu)予硫化(hua)(hua)(hua)膠(jiao)各(ge)種(zhong)特(te)殊的性(xing)能,也加(jia)(jia)入相應(ying)的各(ge)種(zhong)添(tian)加(jia)(jia)劑。硫化(hua)(hua)(hua)劑是(shi)(shi)各(ge)種(zhong)有(you)機過(guo)氧(yang)化(hua)(hua)(hua)物或加(jia)(jia)成(cheng)反(fan)應(ying)催(cui)化(hua)(hua)(hua)劑。
加工(gong)成型方法如圖(tu)所示。一次硫化的目(mu)的是進行高分(fen)子(zi)鏈的交聯反應;二次硫化的目(mu)的是進行補充(chong)交聯、驅除硫化劑分(fen)解產物(wu)和其他揮發性(xing)化合物(wu)以穩定硫化膠(jiao)的各項性(xing)能。常用的設備有開放式煉膠(jiao)機(ji)、捏合機(ji)及真空密(mi)煉機(ji)。
主要性能
(1)高(gao)(gao)溫(wen)(wen)(wen)(wen)性(xing)(xing)(xing)(xing)(xing)(xing)能(neng)(neng)。硅(gui)(gui)橡(xiang)(xiang)(xiang)膠(jiao)顯(xian)(xian)著的(de)(de)(de)特征是(shi)高(gao)(gao)溫(wen)(wen)(wen)(wen)穩定(ding)性(xing)(xing)(xing)(xing)(xing)(xing),雖然常溫(wen)(wen)(wen)(wen)下(xia)硅(gui)(gui)橡(xiang)(xiang)(xiang)膠(jiao)的(de)(de)(de)強度僅是(shi)天(tian)然橡(xiang)(xiang)(xiang)膠(jiao)或某些合(he)成橡(xiang)(xiang)(xiang)膠(jiao)的(de)(de)(de)一半,但在200℃以(yi)上(shang)的(de)(de)(de)高(gao)(gao)溫(wen)(wen)(wen)(wen)環境下(xia),硅(gui)(gui)橡(xiang)(xiang)(xiang)膠(jiao)仍能(neng)(neng)保持(chi)一定(ding)的(de)(de)(de)柔韌性(xing)(xing)(xing)(xing)(xing)(xing)、回彈性(xing)(xing)(xing)(xing)(xing)(xing)和(he)表面硬度,且力學性(xing)(xing)(xing)(xing)(xing)(xing)能(neng)(neng)無(wu)明(ming)顯(xian)(xian)變(bian)化(hua)(hua)。(2)低溫(wen)(wen)(wen)(wen)性(xing)(xing)(xing)(xing)(xing)(xing)能(neng)(neng)硅(gui)(gui)橡(xiang)(xiang)(xiang)膠(jiao)的(de)(de)(de)玻璃化(hua)(hua)溫(wen)(wen)(wen)(wen)度一般為(wei)-70~-50℃,特殊配方(fang)可達-100℃,表明(ming)其(qi)低溫(wen)(wen)(wen)(wen)性(xing)(xing)(xing)(xing)(xing)(xing)能(neng)(neng)優(you)異。這對(dui)航空(kong)、宇(yu)航工業的(de)(de)(de)意(yi)義重(zhong)大。(3)耐(nai)(nai)候性(xing)(xing)(xing)(xing)(xing)(xing)硅(gui)(gui)橡(xiang)(xiang)(xiang)膠(jiao)中Si-O-Si鍵對(dui)氧、臭氧及紫(zi)外線(xian)等十分穩定(ding),在不(bu)加任何添加劑的(de)(de)(de)情況下(xia),就具(ju)有(you)優(you)良(liang)的(de)(de)(de)耐(nai)(nai)候性(xing)(xing)(xing)(xing)(xing)(xing)。(4)電氣性(xing)(xing)(xing)(xing)(xing)(xing)能(neng)(neng)。硅(gui)(gui)橡(xiang)(xiang)(xiang)膠(jiao)具(ju)有(you)優(you)異的(de)(de)(de)絕緣性(xing)(xing)(xing)(xing)(xing)(xing)能(neng)(neng),耐(nai)(nai)電暈性(xing)(xing)(xing)(xing)(xing)(xing)和(he)耐(nai)(nai)電弧(hu)性(xing)(xing)(xing)(xing)(xing)(xing)也非(fei)常好。(5)物理機(ji)械性(xing)(xing)(xing)(xing)(xing)(xing)能(neng)(neng)。硅(gui)(gui)橡(xiang)(xiang)(xiang)膠(jiao)常溫(wen)(wen)(wen)(wen)下(xia)的(de)(de)(de)物理機(ji)械性(xing)(xing)(xing)(xing)(xing)(xing)能(neng)(neng)比(bi)通(tong)用(yong)橡(xiang)(xiang)(xiang)膠(jiao)差(cha),但在150℃的(de)(de)(de)高(gao)(gao)溫(wen)(wen)(wen)(wen)和(he)-50℃的(de)(de)(de)低溫(wen)(wen)(wen)(wen)下(xia),其(qi)物理機(ji)械性(xing)(xing)(xing)(xing)(xing)(xing)能(neng)(neng)優(you)于通(tong)用(yong)橡(xiang)(xiang)(xiang)膠(jiao)。(6)耐(nai)(nai)油及化(hua)(hua)學試劑性(xing)(xing)(xing)(xing)(xing)(xing)。普(pu)通(tong)硅(gui)(gui)橡(xiang)(xiang)(xiang)膠(jiao)具(ju)有(you)中等的(de)(de)(de)耐(nai)(nai)油、耐(nai)(nai)溶劑性(xing)(xing)(xing)(xing)(xing)(xing)能(neng)(neng)。(7)氣體透過(guo)性(xing)(xing)(xing)(xing)(xing)(xing)能(neng)(neng)。室溫(wen)(wen)(wen)(wen)下(xia)硅(gui)(gui)橡(xiang)(xiang)(xiang)膠(jiao)對(dui)空(kong)氣、氮、氧、二氧化(hua)(hua)碳等氣體的(de)(de)(de)透氣性(xing)(xing)(xing)(xing)(xing)(xing)比(bi)天(tian)然橡(xiang)(xiang)(xiang)膠(jiao)高(gao)(gao)出(chu)30-50倍。(8)生(sheng)理惰性(xing)(xing)(xing)(xing)(xing)(xing)。硅(gui)(gui)橡(xiang)(xiang)(xiang)膠(jiao)無(wu)毒,無(wu)味,無(wu)嗅,與(yu)人體組織不(bu)粘連,具(ju)有(you)抗凝(ning)血(xue)作(zuo)用(yong),對(dui)肌體組織的(de)(de)(de)反應性(xing)(xing)(xing)(xing)(xing)(xing)非(fei)常少(shao)。特別適(shi)合(he)作(zuo)為(wei)醫(yi)用(yong)材料。
硅橡膠的用量
據中國(guo)汽(qi)(qi)(qi)車(che)工業協(xie)會統計(ji),2012年,汽(qi)(qi)(qi)車(che)產(chan)(chan)銷分別達(da)到1927.18萬(wan)輛(liang)和(he)1930.64萬(wan)輛(liang),同(tong)比(bi)分別增(zeng)(zeng)長(chang)4.63%和(he)4.33%,汽(qi)(qi)(qi)車(che)工業硅橡(xiang)膠(jiao)的用(yong)量約達(da)2.0萬(wan)t。根據觀(guan)研天下(xia)的新研究,增(zeng)(zeng)加(jia)有(you)機硅材(cai)料在(zai)汽(qi)(qi)(qi)車(che)零部(bu)件(jian)方面的用(yong)量,可以(yi)(yi)大幅度提高汽(qi)(qi)(qi)車(che)的安全性(xing)能,因此(ci),汽(qi)(qi)(qi)車(che)產(chan)(chan)量和(he)單車(che)用(yong)量水(shui)平的提高都將(jiang)推動汽(qi)(qi)(qi)車(che)工業對硅橡(xiang)膠(jiao)需求的增(zeng)(zeng)加(jia)。國(guo)家鼓勵自(zi)(zi)(zi)主(zhu)品牌(pai)的汽(qi)(qi)(qi)車(che)發展(zhan),關鍵汽(qi)(qi)(qi)車(che)零部(bu)件(jian)實現自(zi)(zi)(zi)主(zhu)化,《2012年度黨政(zheng)機關公務用(yong)車(che)選用(yong)車(che)型目錄(征求意見(jian)稿)》為(wei)自(zi)(zi)(zi)主(zhu)品牌(pai)擴大在(zai)政(zheng)府采購(gou)的市場份(fen)額,為(wei)改變目前(qian)國(guo)內政(zheng)府采購(gou)以(yi)(yi)合(he)資品牌(pai)產(chan)(chan)品為(wei)主(zhu)的局面提供了保障(zhang)。促進(jin)自(zi)(zi)(zi)主(zhu)品牌(pai)發展(zhan),國(guo)產(chan)(chan)汽(qi)(qi)(qi)車(che)業的繁榮將(jiang)為(wei)汽(qi)(qi)(qi)車(che)膠(jiao)的應(ying)用(yong)提供有(you)力保障(zhang)。預測(ce)未來(lai)3年,我(wo)國(guo)室溫(wen)硫化硅橡(xiang)膠(jiao)在(zai)汽(qi)(qi)(qi)車(che)行(xing)業將(jiang)以(yi)(yi)年均20%增(zeng)(zeng)長(chang)。
此外,硅(gui)橡(xiang)(xiang)膠(jiao)(jiao)是重要(yao)的(de)(de)(de)非(fei)石(shi)油(you)(you)基合(he)(he)成(cheng)橡(xiang)(xiang)膠(jiao)(jiao),約占非(fei)石(shi)油(you)(you)基合(he)(he)成(cheng)橡(xiang)(xiang)膠(jiao)(jiao)消費量的(de)(de)(de)98%。但(dan)因為石(shi)油(you)(you)價(jia)(jia)格(ge)的(de)(de)(de)大(da)(da)幅上漲,同時(shi)我國在硅(gui)橡(xiang)(xiang)膠(jiao)(jiao)的(de)(de)(de)關(guan)鍵(jian)原料有(you)機硅(gui)單體(ti)(ti)(ti)的(de)(de)(de)生(sheng)(sheng)產(chan)技術方(fang)面取(qu)得突(tu)破,有(you)機硅(gui)單體(ti)(ti)(ti)的(de)(de)(de)生(sheng)(sheng)產(chan)技術在2005年前被(bei)幾(ji)家跨國公司壟斷,但(dan)目前我國已發展成(cheng)為全球有(you)機硅(gui)單體(ti)(ti)(ti)第1大(da)(da)國,這2個方(fang)面原因使硅(gui)橡(xiang)(xiang)膠(jiao)(jiao)的(de)(de)(de)價(jia)(jia)格(ge)從(cong)2011年起開始低于石(shi)油(you)(you)基合(he)(he)成(cheng)橡(xiang)(xiang)膠(jiao)(jiao),僅約為大(da)(da)宗石(shi)油(you)(you)基橡(xiang)(xiang)膠(jiao)(jiao)的(de)(de)(de)80%~90%,成(cheng)為廉價(jia)(jia)的(de)(de)(de)合(he)(he)成(cheng)橡(xiang)(xiang)膠(jiao)(jiao),并開始大(da)(da)規(gui)模替代(dai)石(shi)油(you)(you)基合(he)(he)成(cheng)橡(xiang)(xiang)膠(jiao)(jiao)。這將極(ji)大(da)(da)拓展有(you)機硅(gui)產(chan)業的(de)(de)(de)市場空間(jian),同時(shi)將帶動硅(gui)油(you)(you)、硅(gui)烷偶聯劑和硅(gui)樹(shu)脂等其他(ta)有(you)機硅(gui)產(chan)品的(de)(de)(de)消費。